Human adenoviruses are major causes of acute infections of the respiratory, gastrointestinal tract, and the eye. In severe cases of ocular infections, such as those occurring in epidemic keratoconjunctivitis, adenovirus can cause significant morbidity and loss of visual acuity. At the present time, there are few if any effective antiviral agents that have been approved for the treatment of adenovirus eye infections. The studies proposed here seek to remedy this situation by capitalizing on the significant progress made during the previous funding period as well as our new preliminary studies. Specifically, we propose to undertake a systematic and multidisciplinary investigation of the antiviral activities of naturally occurring antimicrobial peptides (AMPs) and novel synthetic small molecules. The major goal of the proposed studies is to determine precisely how AMPs and synthetic small molecules intervene in the adenovirus cell entry pathway. This goal will be achieved by: 1) identifying the adenoviral coat proteins that are recognized by AMPs and synthetic molecules;2) analyzing the precise adenovirus binding properties of AMPs;3) solving the three-dimensional structure of adenovirus-AMP complexes by X-ray diffraction and cryoelectron microscopy;and 4) employing high-throughput screens of combinatorial libraries to discover novel synthetic small molecules that restrict adenovirus infection. These investigations should not only improve our knowledge of adenovirus structure and the mechanisms involved in host cell entry but could also lead to the development of new treatments for adenovirus-induced ocular diseases. PUBLIC HEALTH RELEVANCE: Human adenoviruses infections are generally self-limiting, however fatal disseminated adenovirus infections are appearing with increasing frequency in immunocompromised patients. Moreover, effective treatments for adenovirus ocular infections remain an unmet medical need. The studies proposed here seek to improve the prospects of developing better antiviral therapeutics by analyzing the inhibitory activities of naturally occurring antimicrobial peptides as well as new synthetic small molecules. )